1.
Alternative donor BMT with post-transplant cyclophosphamide as initial therapy for acquired severe aplastic anemia
DeZern, A., Zahurak, M. L., Symons, H. J., Cooke, K. R., Huff, C. A., Jain, T., Swinnen, L. J., Imus, P. H., Wagner-Johnston, N. D., Ambinder, R. F., et al
Blood. 2023
Abstract
Severe aplastic anemia (SAA) is a marrow failure disorder with high morbidity and mortality. It is treated with bone marrow transplantation (BMT) for those with fully matched donors or immunosuppressive therapy (IST) for those who lack such a donor, which is often the case for underrepresented minorities. We conducted a prospective phase II trial of reduced-intensity conditioning HLA-haplo BMT and post-transplantation cyclophosphamide (PTCy)-based graft-versus-host (GVHD) prophylaxis as initial therapy for patients with SAA. The median age was 25 (range 3-63) years and the median follow-up was 40.9 months (95% CI: 29.4, 55.7 mos). Over 35% of enrollment was from underrepresented racial/ethnic groups. The cumulative incidence of grade II-IV aGVHD at day 100 is 7% (95% CI: NA, 17%) and chronic GVHD at 2 years is 4% (95% CI: NA, 11%). The overall survival for 27 patients is 92% (95% CI: 83,100%) at one, two, and three years. The first 7 patients received lower dose total body irradiation (200 versus 400 cGY), but these patients were more likely to have graft failure, 3 of 7, compared to 0 out of 20 patients in the higher dose group (p=0.01, Fisher exact). HLA-haploidentical BMT with PTCy using 400cGY total body irradiation resulted in 100% overall survival with minimal GVHD in 20 consecutive patients. Not only does this approach avoid the ramifications of IST and its low failure-free survival, but also the use of haploidentical donors expands access to BMT across all populations. Clinical trial: NCT02833805.
2.
Haploidentical BMT for severe aplastic anemia with intensive GVHD prophylaxis including posttransplant cyclophosphamide
DeZern, A. E., Zahurak, M. L., Symons, H. J., Cooke, K. R., Rosner, G. L., Gladstone, D. E., Huff, C. A., Swinnen, L. J., Imus, P., Borrello, I., et al
Blood advances. 2020;4(8):1770-1779
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Abstract
Severe aplastic anemia (SAA) is a stem cell disorder often treated with bone marrow transplantation (BMT) to reconstitute hematopoiesis. Outcomes of related HLA-haploidentical (haplo) donors after reduced-intensity conditioning with intensive graft-versus-host disease (GVHD) prophylaxis including posttransplantation cyclophosphamide are presented here from 37 SAA, 20 relapsed/refractory (R/R), and 17 treatment-naive (TN) SAA patients. Median follow-up is 32 months (90% confidence interval [CI], 29-44). The median age was 25 (range, 4-69) years. The median time to neutrophil recovery was 17 days (range, 15-88). Four of 37 patients (11%) experienced graft failure (GF). There was 1 primary GF of 20 patients in the R/R group and 3 of 17 in the TN group at 200 cGy (1 primary, 2 secondary), but none in the 10 patients who received 400 cGy total body irradiation. Two patients with GF succumbed to infection and 2 were rescued with second haplo BMT. The overall survival for all patients is 94% (90% CI, 88-100) at 1 and 2 years. The cumulative incidence of grade II-IV acute GVHD at day 100 is 11%. The cumulative index of chronic GVHD at 2 years is 8%. Similar results were seen in 10 SAA patients who received the identical nonmyeloablative regimen with posttransplant cyclophosphamide but matched donor transplants. Haplo BMT with posttransplant cyclophosphamide represents a potential cure in SAA, with all 20 R/R currently alive, disease-free, and with no evidence of active GVHD. Extending this approach to TN patients was associated with higher GF rates, but an increase in total body irradiation dose to 400 cGy was associated with durable engraftment without greater early toxicity. Nonmyeloablative haplo BMT in TN SAA could lead to a paradigm shift, such that essentially all patients can proceed quickly to safe, curative BMT. These trials were registered at www.cincialtrials.gov as #NCT02224872) and #NCT02833805.